I understand why a portion of the vocal PS3 community is angry about this, as paying for a game and then not being able to get an online match together is really annoying. I probably hit around a 70% success ratio over the period of four days which is not too bad, but still, not what a consumer would ultimately hope for.
Fat Princess is a fairly deep strategic kind of game. It's really easy to get flustered and subsequently killed countless times unless you get a handle on the classes first. Playing through the criminally short single-player story mode is the best way to experiment in this respect, but amidst the 32-player online carnage, you'd better know what you're doing if you want to hit the top of the leaderboards.

The Mage waves his stick, looks pensive, and then gets nailed by an off-screen archer.
My favored tactics right now go as follows: Play as the Worker class initially, with a view to harvesting as much wood and metal as you can in the first five or so minutes of the game. The Workers are able to build structures, upgrade the class huts and at a pinch land the killing blow on a damaged enemy.
After I've gathered a ton of supplies (and providing I can get to the castle's inner santum before another Worker starts to spend the harvested supplies, I try to upgrade the Priest class first -- this then grants access to the Dark Priest powers as well as the Light Priest powers. I ditch my Worker's hat, become a Priest and head out into the battlefield, taking on anyone and everyone I come across.
It's my opinion that the Priest is the best class in the game, bar none. I'll be happy to read comments at the end of this article telling me that "I suck" and "you're wrong" but honestly I don't care. With a little skill and lots of running and strafing I rarely get killed, while all the time I'm healing my team's Archers, Warriors, Mages, Priests and Workers as well as draining the enemies of their health and cursing multiple targets. It's rare that I finish lower than third place at the end of each match, and that's just fine with me.